CN109973021B

CN109973021B - Drill bit of integrated nozzle structure

Info

Publication number: CN109973021B
Application number: CN201910335550.1A
Authority: CN
Inventors: 王巍雄; 文磊; 张汝南; 匡小围
Original assignee: Seed Technologies Corp Ltd
Current assignee: Seed Technologies Corp Ltd
Priority date: 2019-04-24
Filing date: 2019-04-24
Publication date: 2020-09-01
Anticipated expiration: 2039-04-24
Also published as: CN109973021A

Abstract

A drill bit integrated with a nozzle structure comprises a matrix, wherein a cavity is arranged in the matrix, a nozzle is arranged on the matrix, and the nozzle is communicated with the cavity; the nozzle is characterized by comprising a nozzle flow channel, a nozzle inner orifice and a nozzle outer orifice, wherein the nozzle outer orifice is oval, and the nozzle and a tire body are integrally manufactured. According to the structure of the invention, the jet flow with the same strength can be enabled, the distribution range becomes wider, the jet flow of the nozzle can better clean the cutting teeth and more quickly cool the cutting surface, thereby improving the mechanical drilling speed and simultaneously prolonging the service life of the cutting teeth and the drill bit; the position of a long shaft of the nozzle and the angle of the nozzle can be accurately aligned by adopting an additive manufacturing mode; the manufacturing cost and the generation period are saved, and the reliability and the safety of the drill bit are enhanced; the strength of the drill bit body is guaranteed not to be weakened, the nozzle outlet is guaranteed not to be blocked by particles contained in drilling fluid easily, the risk of cracking of a nozzle hole is reduced, and the risk that the nozzle drops to the bottom of the well is eliminated.

Description

Drill bit of integrated nozzle structure

Technical Field

The invention relates to a drill bit used in the field of geological exploration such as petroleum and natural gas, in particular to a drill bit with an integrated nozzle structure, which is designed and manufactured by using technologies such as additive manufacturing and the like.

Background

At present, a latest drill bit manufacturing process is to manufacture a drill bit by an additive manufacturing (commonly referred to as 3D printing). Due to the technical characteristics of additive manufacturing, the manufactured metal component has good internal quality, high forming speed and small residual stress, and is particularly suitable for high-temperature alloys and refractory metal materials. Therefore, the drill bit manufactured by the additive manufacturing method has high wear resistance and high toughness, so that the application range of the drill bit is wider than that of the traditional drill bit.

In order to discharge a large amount of rock debris generated during drilling of a drill bit, a high-pressure pump is generally arranged on the ground, then specially prepared drilling fluid is pumped into a drill rod from the ground and is led to the drill bit at the bottom of a well all the time, high-speed jet flow is formed through a nozzle arranged in a chip removal groove of the drill bit, the bottom of the well is washed, the rock debris is taken away, the rock debris flows into a well hole annular space through the chip removal groove, and finally the rock debris returns to the ground along with drilling fluid flow. On the other hand, the drill bit can generate a large amount of heat in the drilling process, and when the temperature exceeds 775 ℃, the structure of the cutting teeth on the drill bit can be rapidly decayed, so that the abrasion is increased; therefore, the other function of the nozzle jet flow of the drill bit is to scour the working surface of the cutting teeth, take away heat generated by rock breaking in time and protect the drill bit.

For more efficient removal of debris and cooling of the drill bit, the water power of the nozzles needs to be increased. This can be achieved by increasing the drilling fluid flow or by reducing the nozzle flow area, both methods essentially increasing the jet velocity. However, an increase in flow rate causes an increase in on-way pressure loss, ultimately limited by the pump pressure; the smaller nozzle bore also increases the risk of the nozzle opening becoming blocked by foreign objects, such as the aged chipping of certain rubber components in upstream tools, or the inadvertent dropping of foreign objects during the connection of drill rods, etc. In addition, too high a jet velocity tends to cause erosive damage to the bit body and the nozzle. How to reasonably design the nozzle to enable the limited water power to be efficiently utilized, the cutting teeth can be rapidly discharged with chips and cooled, and meanwhile, the excessive pumping pressure requirement and the erosion risk are not caused, which is always the key point and the difficulty in the design of the drill bit. The traditional nozzle design method is to complete initial design according to a hydraulic calculation formula and some empirical coefficients and then check the design through a performance test. The method has the advantages of low calculation precision, poor reliability, long period and high cost. After the nozzle is designed, the nozzle is usually fastened in a nozzle hole of a bit body through threaded connection and sealed by adopting an O-shaped ring, and a retainer ring is added to a nozzle hole to prevent the nozzle from falling out in some designs; or the nozzle is directly welded in the nozzle hole in a brazing mode, so that threads, a sealing ring and a check ring are not needed; or directly using the nozzle hole on the drill body to provide the jet flow without installing the nozzle, thereby saving the cost but causing serious erosion to the nozzle hole when the jet flow speed is high. To further enhance the ability of the nozzle to chip and cool the tooth surfaces, some designs have proposed using nozzles with non-circular cross-sections. For example, patent CN2127427Y proposes a hydraulic nozzle with an oval cross section for drag bit, so as to increase the impact width and pressure gradient of the jet on the well bottom, thereby playing a role in stronger assisting in breaking rock and flushing the well bottom. Patent CN204552623U is directed to PDC bits, a string nozzle proposed, and mentions a nozzle that can be further made elliptical. Patent CN204552622U proposes the use of oblong water holes for PDC bits. The coverage area of the water hole outflow fan angle is greatly increased compared with the traditional circular nozzle. Patent CN208168805U proposes, for PDC bits and other bits, nozzles with elongated outlet cross-sections to increase the extent of the outlet jet covering the cutter. Patent US5358063 proposes a divergent water hole with an elliptical outlet cross section to reduce the outflow rate of the water hole and reduce erosion. Patent CN107405687A proposes a method for manufacturing a PDC bit body with water holes by using a metal additive manufacturing method, and the nozzles are still installed separately.

In the above patents, the improvement idea of the hydraulic nozzle of the drill bit is basically similar, that is, the width of the outflow of the jet flow is increased by changing the circular shape into an elliptical shape or a long shape, so as to achieve better chip removal and cooling effects. But include some specific disadvantages as follows: 1. due to the fact that the elongated slot is formed in the bit body, the anti-torsion strength of the drill bit is reduced to a certain extent, and the longer the drill bit is in the length direction, the more serious the strength reduction is; 2. if the width direction of the slot is too narrow, large particles in slurry are difficult to discharge from the nozzle, the nozzle is easy to block, and the flow of the nozzle is limited, so that unsmooth chip removal and poor cooling are caused; 3. for water holes with narrow inlets and wide outlets and the nozzle US5358063CN204552622U, if the cross-sectional area is gradually widened from the inlet to the outlet, the hydraulic energy is obviously reduced, thus being not beneficial to chip removal and cooling, although being helpful for reducing erosion; 4. for the design patent CN2127427Y that adopts an elliptical nozzle, since the nozzle is still an independent part, the long axis direction of the nozzle needs to be adjusted to be parallel to the teeth distribution direction or form a certain angle during installation, which requires an additional positioning mechanism between the nozzle and the water hole, resulting in additional cost; 5. with the newly published water-bored bit body CN107405687A made using additive manufacturing techniques, the nozzles are still conventional separate parts that need to be individually installed. In general, the above-mentioned prior patents, while proposing improvements to the nozzle design, bring new problems, mainly including: after the nozzle is lengthened in one dimension direction, although the jet width can be increased, the strength of the drill bit body is reduced; in order to keep the outflow area constant, the nozzles must be reduced in the other dimension, thus increasing the risk of the nozzles becoming clogged by particles in the drilling fluid; the hard alloy nozzle with the non-circular section has the problems of increased manufacturing cost, difficult positioning and the like.

Disclosure of Invention

The invention aims at the problems that the prior art is insufficient in flushing and cooling capacities, the strength of a bit body is reduced due to the increase of the width of a nozzle, the nozzle is easy to be blocked, the nozzle is difficult to install, the manufacturing cost is high, the manufacturing period is long, and the like; a drill bit integrated with a nozzle structure and a method of manufacturing the same are provided.

In order to solve the technical problems, the invention adopts the technical scheme that:

a drill bit integrated with a nozzle structure comprises a matrix, wherein a cavity is arranged in the matrix, a nozzle is arranged on the matrix, and the nozzle is communicated with the cavity; the nozzle is characterized by comprising a nozzle flow channel, a nozzle inner orifice and a nozzle outer orifice, wherein the nozzle outer orifice is oval, and the nozzle and a tire body are integrally manufactured.

Optionally, the matrix and the nozzle are manufactured by additive manufacturing, including selective laser sintering, laser melting, electron beam melting, and the like.

Optionally, the material of the matrix and the nozzle is nickel-based alloy powder and tungsten carbide particles.

Optionally, 45 wt% -72 wt% of tungsten carbide powder; 28 wt% -55 wt% of nickel-based powder.

Optionally, the granularity of the tungsten carbide powder is 80-400 meshes, and the granularity of the nickel-based powder is 150-350 meshes.

Optionally, the nickel-based powder comprises 1.5 wt% -2.5 wt% of B, 3 wt% -4 wt% of Si, and the balance of Ni.

Optionally, the carcass is provided with blades, and the cutting teeth are arranged on the blades.

Further, the cutter is a PDC cutter.

Optionally, one or more nozzles are provided.

Optionally, one or more blades are provided.

Optionally, one or more cutting teeth are provided on the blade.

Optionally, the blades and the nozzle are spaced apart.

Alternatively, to ensure a constant total nozzle outflow area, the area of the outer orifice of the elliptical nozzle should be comparable to the area of the outer orifice of a conventional circular nozzle. Assuming that the inner diameter d of the outer orifice of the perfect circular nozzle is obtained according to the design method of the conventional perfect circular nozzle, the major axis 2a and the minor axis 2b of the outer orifice of the elliptical nozzle of the present invention should satisfy the following constraint of constant area:

in the formula, a is the radius of the long axis of the outer orifice of the elliptical nozzle with the same area, b is the radius of the short axis of the outer orifice of the elliptical nozzle with the same area, and d is the inner diameter of the outer orifice of the circular nozzle with the same area.

Further, the major axis of the outer orifice of the elliptical nozzle must not be oversized to ensure that the strength of the bit body is not compromised. Since the nozzle and the carcass are integrally manufactured, the major axis 2a of the oval nozzle outer orifice does not exceed the outer diameter D of the conventional right circular nozzle outer orifice of the same area, that is:

d≤2a≤D (2)

wherein D is the outer diameter of the outer orifice of the circular nozzle with the same area.

The value range of the short axis 2b can be determined according to the formula (1):

further, the minimum value of the short axis 2b needs to be defined as t, so as to further obtain according to the formula (3):

in the formula, t is the minimum value range of the minor axis 2 b.

Furthermore, the value range of t is 2mm-5 mm.

Optionally, the ratio k of the major axis and the minor axis of the outer orifice of the elliptical nozzle is not too large, and the value range of k is as follows:

in the formula, k is the ratio of the outer diameter of the elliptical nozzle to the major axis.

Optionally, in the streamline direction of the nozzle flow channel, the nozzle inner orifice is a perfect circle, the traditional perfect circle section design is reserved for the part of the nozzle flow channel close to the nozzle inner orifice, and the section shape of the nozzle flow channel smoothly transits from the perfect circle to the ellipse along the center line of the nozzle flow channel.

Further, the range c in which the elliptical cross-section is maintained in the smooth transition may be selected as the distance c of the nozzle flow passage near the nozzle outer orifice, b-3 b.

Optionally, the centerline of the nozzle flowpath may be straight or may be any smooth curve, which may be adjusted based on the nozzle location of the bit body to take full advantage of the manufacturing benefits of additive manufacturing.

A method of manufacturing a drill bit: according to formula (2): d is less than or equal to 2a and less than or equal to D, and the maximum possible distance is selected

According to formula (1):

to obtain

In the formula, a is the radius of the long axis of the outer orifice of the elliptical nozzle with the same area, b is the radius of the short axis of the outer orifice of the elliptical nozzle with the same area, D is the inner diameter of the outer orifice of the circular nozzle with the same area, and D is the outer diameter of the outer orifice of the circular nozzle with the same area.

Alternatively, according to formula (4):

judging whether the calculated 2b is smaller than t; if the value is smaller than t, 2 b-t is taken, namely b-t/2; in the formula, t is the minimum value of the minor axis 2 b.

Furthermore, the value range of t is 2mm-5 mm.

Alternatively, according to equation (5):

if k is>4, further increasing the value of b, or further decreasing the value of a and recalculating b until k is satisfied<4; in the formula, k is the ratio of the outer diameter of the elliptical nozzle to the major axis.

Alternatively, according to equation (5):

if k occurs<1.25, selecting a proper amplification D value under the condition of ensuring that the strength of the drill body is enough, or selecting a proper reduction D value under the condition of ensuring that the hydraulic power is enough; in the formula, k is the ratio of the outer diameter of the elliptical nozzle to the major axis.

Compared with the prior art, the invention has the advantages that:

1. the invention adopts the nozzle with the oval section, under the condition of the same cross section area, the nozzle with the oval section can enable the jet flow with the same strength to be wider in distribution range compared with the traditional nozzle with the circular section, when the long axis direction of the jet flow is parallel to the direction of the cutting surface of the blade, the jet flow of the nozzle can better clean the cutting teeth and more quickly cool the cutting surface, thereby improving the mechanical drilling speed and prolonging the service life of the cutting teeth and the drill bit.

2. Because the nozzle is directly printed and formed together with the drill bit body by adopting an additive manufacturing method, the position of the long axis of the nozzle and the angle of the nozzle can be accurately adjusted compared with the traditional independent hard alloy nozzle.

3. Because the nozzle and the bit body are integrated, a separate nozzle does not need to be machined, and the nozzle does not need to be installed through threads or brazing, so that the manufacturing cost and the production period are saved.

4. Because the nozzle and the drill bit body are integrated, the risk that the nozzle falls to the bottom of the well in the drilling process does not exist, and the reliability and the safety of the drill bit are enhanced.

5. The area of the elliptical nozzle should be comparable to the outlet area of a conventional circular nozzle to ensure a constant total nozzle exit flow area.

6. The maximum value of the major axis of the ellipse of the cross section of the nozzle is limited, so that the strength of the drill bit body is ensured not to be weakened.

7. The minimum value of the elliptical short axis of the cross section of the nozzle is limited, so that the outlet of the nozzle is not easily blocked by particles contained in the drilling fluid.

8. Due to the fact that the ratio of the long axis and the short axis of the oval shape of the cross section of the nozzle is limited, stress concentration at the sharp points of the two ends of the nozzle hole is prevented when the ratio of the long axis and the short axis is too large, and therefore the risk of cracking of the nozzle hole is reduced.

Drawings

FIG. 1 is a schematic view of a conventional right circular nozzle.

Wherein D is the outer diameter of the outer orifice of the circular nozzle with the same area, and D is the inner diameter of the outer orifice of the circular nozzle with the same area.

Fig. 2 is a block diagram of a drill bit incorporating an elliptical nozzle structure of the present invention.

Fig. 3 is a cross-sectional view of a drill bit incorporating an elliptical nozzle structure of the present invention.

Wherein, 1: carcass, 2: nozzle, 3: cavity, 2-3: nozzle flow passage, 2-2: nozzle inner orifice, 2-1: nozzle outer orifice, 4: blade, 5: the cutting teeth c are the range where the nozzle flow passage 2-3 maintains the elliptical cross section.

FIG. 4 is a diagram illustrating the nozzle structure of the embodiment a of the present invention.

FIG. 5 is a diagram illustrating the nozzle structure of the embodiment b of the present invention.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Exemplary embodiments according to the present application will now be described in more detail with reference to the accompanying drawings. These exemplary embodiments may, however, be embodied in many different forms and should not be construed as limited to only the embodiments set forth herein. It is to be understood that these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art, in the drawings, it is possible to enlarge the thicknesses of layers and regions for clarity, and the same devices are denoted by the same reference numerals, and thus the description thereof will be omitted.

With reference to fig. 1 to 3, in some embodiments of the present invention, a drill bit with an integrated nozzle structure is provided, the drill bit includes a casing 1, a cavity 3 is disposed inside the casing 1, a nozzle 2 is disposed on the casing 1, and the nozzle 2 is communicated with the cavity 3; the nozzle is characterized in that the nozzle 2 comprises a nozzle flow passage 2-3, a nozzle inner orifice 2-2 and a nozzle outer orifice 2-1, the nozzle outer orifice 2-1 is oval, and the nozzle 2 and the tire body 1 are integrally manufactured.

In some embodiments, the carcass 1 and nozzle 2 are manufactured by additive manufacturing, including selective laser sintering, laser melting, electron beam melting, and the like.

In some embodiments, the materials of the matrix 1 and the nozzle 2 are nickel-based alloy powder plus cast tungsten carbide particles.

In some embodiments, 45 wt% to 72 wt% tungsten carbide powder; 28 wt% -55 wt% of nickel-based powder.

In some embodiments, the tungsten carbide powder has a particle size of 80 mesh to 400 mesh and the nickel-based powder has a particle size of 150 mesh to 350 mesh.

In some embodiments, the nickel-based powder includes 1.5 wt% to 2.5 wt% of B, 3 wt% to 4 wt% of Si, and the balance Ni.

Example 1: WC powder with the granularity of 80 meshes and nickel-based powder with the granularity of 150 meshes are mixed according to the mass ratio of 65: 35. The hardness, the compression strength, the compression fracture deformation rate, the bending strength, the relative wear resistance and the relative corrosion resistance of the sample prepared in the embodiment 1 of the invention are tested, and the test result shows that the hardness, the compression strength and the compression fracture deformation rate of the sample prepared in the embodiment 1 of the invention are HRA78, 1774MPa, 14.3 percent, 1302MPa, 78.5 percent and 28.4 percent.

Example 2: WC powder with the granularity of 80 meshes and nickel-based powder with the granularity of 150 meshes are mixed according to the mass ratio of 70: 30. The sample prepared in example 2 of the present invention was tested for hardness, compressive strength, compression fracture deformation rate, bending strength, relative wear resistance and relative corrosion resistance, and the test results showed that the sample prepared in example 2 of the present invention had a hardness of HRA85.5, a compressive strength of 1833MPa, a compression fracture deformation rate of 15.1%, a bending strength of 1267MPa, a relative wear resistance of 82.7 and a relative corrosion resistance of 30.7.

Example 3: WC powder with the granularity of 80 meshes and nickel-based powder with the granularity of 150 meshes are mixed according to the mass ratio of 72: 28. The sample prepared in example 3 of the present invention was tested for hardness, compressive strength, compression fracture deformation rate, bending strength, relative wear resistance and relative corrosion resistance, and the test results showed that the sample prepared in example 3 of the present invention had a hardness of HRA82.5, a compressive strength of 1873MPa, a compression fracture deformation rate of 14.1%, a bending strength of 1291MPa, a relative wear resistance of 77.4 and a relative corrosion resistance of 28.2.

In some embodiments, the carcass 1 is provided with blades 4, and the cutting teeth 5 are provided on the blades 4.

Further, the cutter 5 is a PDC cutter.

In some embodiments, one or more nozzles 2 are provided.

In some embodiments, one or more blades 4 are provided.

In some embodiments, one or more cutting teeth 5 are provided on blade 4.

In some embodiments, the blades 4 and the nozzle 2 are spaced apart.

In some embodiments, the number of blades 4 is set to 6, and the number of nozzles 2 is also set to 6.

In some embodiments, to ensure a constant total nozzle outflow area, the area of the elliptical nozzle outer orifice 2-1 should be comparable to the area of a conventional right circular nozzle outer orifice. Assuming that the inner diameter d of the outer orifice of the perfect circular nozzle is obtained according to the design method of the conventional perfect circular nozzle, the major axis 2a and the minor axis 2b of the outer orifice 2-1 of the elliptical nozzle of the present invention should satisfy the following constraint of constant area:

wherein, a is the radius of the major axis of the outer orifice of the elliptical nozzle with the same area, b is the radius of the minor axis of the outer orifice of the elliptical nozzle with the same area, and d is the radius of the outer orifice of the circular nozzle with the same area

The inner diameter of the orifice.

In some embodiments, the major axis of the outer orifice 2-1 of the elliptical nozzle may not be oversized to ensure that the strength of the bit body is not compromised. Since the nozzle 2 and the carcass 1 are integrally manufactured, the major axis 2a of the elliptical nozzle outer orifice 2-1 does not exceed the outer diameter D of a conventional perfect circular nozzle outer orifice of the same area, that is:

d≤2a≤D (2)

in some embodiments, considering that the short axis direction is too narrow to easily cause particles to block the nozzle, it is necessary to define the minimum value of the short axis 2b as t, so as to further obtain the following formula (3):

in the formula, t is the minimum value range of the minor axis 2 b.

Furthermore, the value range of t is 2mm-5 mm.

In some embodiments, when the ratio of the long axis to the short axis is too large, stress concentration at the two end points of the nozzle hole is easily caused, and the risk of cracking is increased, so the ratio k of the long axis to the short axis of the outer orifice 2-1 of the elliptical nozzle is not easily too large, and the value range of the specified ratio k is as follows:

wherein k is the ratio of the major diameter to the minor axis of the outer orifice of the elliptical nozzle

In some embodiments, the nozzle inner orifice 2-2 is circular in shape in the streamline direction of the nozzle flow passage 2-3, the traditional circular cross-section design of the part of the nozzle flow passage 2-3 close to the nozzle inner orifice 2-2 is reserved, and the cross-sectional shape of the nozzle flow passage 2-3 is smoothly transited from circular to elliptical along the center line of the nozzle flow passage.

Further, the range c where the elliptical cross-section is maintained in the smooth transition may be selected as the distance c from b to 3b of the nozzle flow passage 2-3 near the nozzle outer orifice 2-1. I.e. in the range c, an oval cross-section is maintained (see fig. 3).

In some embodiments, the centerlines of the nozzle flow channels 2-3 may be straight or may be arbitrarily smooth curves that may be adjusted based on the nozzle location of the bit body to take advantage of the manufacturing benefits of additive manufacturing.

In some embodiments of the invention, there is provided a method of manufacturing a drill bit comprising: according to formula (2): d is less than or equal to 2a and less than or equal to D, and the maximum possible distance is selected

According to formula (1):

to obtain

In the formula (I), the compound is shown in the specification,a is the radius of the long axis of the outer orifice of the elliptical nozzle with the same area, b is the radius of the short axis of the outer orifice of the elliptical nozzle with the same area, D is the inner diameter of the outer orifice of the circular nozzle with the same area, and D is the outer diameter of the outer orifice of the circular nozzle with the same area.

In some embodiments, according to formula (4):

Furthermore, the value range of t is 2mm-5 mm.

In some embodiments, according to formula (5):

if k is>4, if the value of b is too small, the value of b needs to be further increased, or the value of a needs to be further reduced and b needs to be recalculated until k is met<4; in the formula, k is the ratio of the outer diameter of the elliptical nozzle to the major axis.

In some embodiments, according to formula (5):

if k occurs<1.25, the D and the D are very close, the outer orifice of the circular nozzle is not easy to deform into the outer orifice of the elliptical nozzle with the same area, or the D value needs to be properly amplified under the condition of ensuring that the strength of the drill body is enough, or the D value needs to be properly reduced under the condition of ensuring that the hydraulic power is enough; in the formula, k is the ratio of the outer diameter of the elliptical nozzle to the major axis.

Example a: scheme one is traditional right circular nozzle (heavy-calibre), scheme two is right traditional circular nozzle (small-calibre), and scheme three is the oval nozzle (small-calibre) that the contrast design was followed to scheme two, wherein D in scheme two equals 20mm, D equals 9mm, and a equals 6.75mm, b equals 3mm in scheme three.

Referring to fig. 4, it can be seen that CFD (computational fluid dynamics) is used for numerical simulation of the flow field for the first, second, and third solutions in example a: the highest value of the flushing speed of the scheme I is 14m/s, the highest value of the flushing speed of the scheme II is 19m/s, and the highest value of the flushing speed of the scheme III is 18 m/s; the speed profile of the scheme I is between 20 and 50mm, the speed profile of the scheme II is between 10 and 50mm, and the speed profile of the scheme III is between 20 and 70 mm.

Example b: scheme one is traditional right circular nozzle (heavy-calibre), scheme two is right traditional circular nozzle (small-calibre), and scheme three is the oval nozzle (small-calibre) that the comparison was designed for with scheme two, wherein D in scheme two equals 16mm, D equals 8mm, and a equals 6mm, b equals 2.67mm in scheme three.

Referring to fig. 5, it can be seen that CFD (computational fluid dynamics) is used for numerical simulation of the flow field for the first, second, and third solutions in example b: the highest value of the flushing speed of the scheme I is 13m/s, the highest value of the flushing speed of the scheme II is 20m/s, and the highest value of the flushing speed of the scheme III is 18 m/s; the speed profile of the scheme I is between 20 and 50mm, the speed profile of the scheme II is between 20 and 50mm, and the speed profile of the scheme III is between 20 and 70 mm.

It can be seen from both examples a and b that the small diameter of the nozzles in the second and third schemes greatly improves the scouring speed of the PDC tooth surfaces, regardless of whether the nozzles are circular or elliptical. However, the speed profile of the right circular nozzle in the second scheme has a steep peak, the hydraulic energy is concentrated, the hydraulic energy is close to the center of the drill bit, and the cooling to the cutting teeth of the nose of the drill bit with heavy working load is insufficient. The elliptical nozzle in the third scheme has a wider peak of a speed profile, a wider coverage range and a capability of better covering each cutting tooth of a nose part with heavier cutting load than a circular nozzle.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A drill bit integrated with a nozzle structure comprises a matrix, wherein a cavity is arranged in the matrix, a nozzle is arranged on the matrix, and the nozzle is communicated with the cavity; the nozzle is characterized by comprising a nozzle flow channel, a nozzle inner orifice and a nozzle outer orifice, wherein the nozzle outer orifice is oval, and the nozzle and a tire body are integrally manufactured; the major axis 2a and minor axis 2b of the elliptical nozzle outer orifice should satisfy the following area-constant constraint:

2. The drill bit with integrated nozzle structure as set forth in claim 1, wherein: the matrix and the nozzle adopt an additive manufacturing mode.

3. The drill bit with integrated nozzle structure as set forth in claim 1, wherein: the material of the matrix and the nozzle adopts nickel-based alloy powder and tungsten carbide particles.

4. The drill bit with integrated nozzle structure as set forth in claim 3, wherein: 45 wt% -72 wt% of tungsten carbide powder; 28 wt% -55 wt% of nickel-based powder.

5. The drill bit with integrated nozzle structure as set forth in claim 3, wherein: the granularity of the tungsten carbide powder is 80-400 meshes, and the granularity of the nickel-based powder is 150-350 meshes.

6. The drill bit with integrated nozzle structure as set forth in claim 3, wherein: the nickel-based powder comprises 1.5-2.5 wt% of B, 3-4 wt% of Si and the balance of Ni.

7. The drill bit with integrated nozzle structure as set forth in claim 1, wherein: in the streamline direction of the nozzle flow passage, the nozzle inner orifice is in a perfect circle shape, the part of the nozzle flow passage close to the nozzle inner orifice is designed with a traditional perfect circle section, and the section shape of the nozzle flow passage is smoothly transited from the perfect circle shape to an ellipse shape along the central line of the nozzle flow passage.

8. The drill bit with integrated nozzle structure as set forth in claim 7, wherein: the range c in which the elliptical cross-section is maintained in the smooth transition is selected to be at a distance c from b to 3b of the nozzle flow passage near the outer orifice of the nozzle.

9. The drill bit with integrated nozzle structure as set forth in claim 1, wherein: the tire body is provided with blades, and the cutting teeth are arranged on the blades.

10. The drill bit with integrated nozzle structure as set forth in claim 1, wherein: the major axis 2a of the elliptical nozzle outer orifice does not exceed the outer diameter D of a conventional right circular nozzle outer orifice of the same area, namely:

d≤2a≤D (2)

11. The drill bit with integrated nozzle structure as set forth in claim 1, wherein: the value range of the short axis 2b can be determined according to the formula (1):

the minimum value of the minor axis 2b needs to be defined as t, so as to further obtain according to the formula (3):

in the formula, t is the minimum value range of the minor axis 2 b.

12. The drill bit with integrated nozzle structure as set forth in claim 11, wherein: the value range of t is 2mm-5 mm.

13. The drill bit with integrated nozzle structure as set forth in claim 1, wherein: the value range of the ratio k of the long axis and the short axis of the outer orifice of the elliptical nozzle is as follows: